fix(providers): show the "Get API Key" link when editing a provider

Providers don't remember which preset they came from, so the edit form had
no preset and only linked the "Website" field; with that field empty the
link vanished. When no preset is selected, look the preset up by the
form's current base URL and use its apiKeyUrl and partner promotion, same
as the add form. If presets sharing that address disagree on the link or
the promotion, don't guess and fall back to the Website field.

tests/hooks/useApiKeyLink.test.tsx

@@ -0,0 +1,157 @@
+import { renderHook } from "@testing-library/react";
+import { describe, expect, it } from "vitest";
+import { useApiKeyLink } from "@/components/providers/forms/hooks/useApiKeyLink";
+
+type Props = Parameters<typeof useApiKeyLink>[0];
+type Entries = Props["presetEntries"];
+
+const claudePreset = (
+  id: string,
+  baseUrl: string,
+  apiKeyUrl: string,
+  partnerPromotionKey?: string,
+) =>
+  ({
+    id,
+    preset: {
+      name: id,
+      websiteUrl: `https://${id}.example`,
+      apiKeyUrl,
+      category: "aggregator",
+      isPartner: Boolean(partnerPromotionKey),
+      partnerPromotionKey,
+      settingsConfig: { env: { ANTHROPIC_BASE_URL: baseUrl } },
+    },
+  }) as unknown as Entries[number];
+
+const render = (props: Partial<Props>) =>
+  renderHook(() =>
+    useApiKeyLink({
+      appId: "claude",
+      category: "aggregator",
+      selectedPresetId: null,
+      presetEntries: [],
+      formWebsiteUrl: "",
+      ...props,
+    }),
+  ).result.current;
+
+describe("useApiKeyLink", () => {
+  const entries = [
+    claudePreset(
+      "hub",
+      "https://hub.example.com",
+      "https://hub.example/key?ref=cc",
+      "hub",
+    ),
+    claudePreset(
+      "other",
+      "https://other.example.com/api",
+      "https://other.example/key",
+    ),
+  ];
+
+  it("edit mode finds the preset by base URL and links its apiKeyUrl", () => {
+    const link = render({
+      presetEntries: entries,
+      formBaseUrl: "  HTTPS://hub.example.com/ ",
+      formWebsiteUrl: "https://my-note.example",
+    });
+    expect(link.shouldShowApiKeyLink).toBe(true);
+    expect(link.websiteUrl).toBe("https://hub.example/key?ref=cc");
+    // 推广语跟着链接一起带出来，和添加页一致
+    expect(link.isPartner).toBe(true);
+    expect(link.partnerPromotionKey).toBe("hub");
+  });
+
+  it("falls back to the website field when no preset matches", () => {
+    const link = render({
+      presetEntries: entries,
+      formBaseUrl: "https://unknown.example.com",
+      formWebsiteUrl: "https://my-note.example",
+    });
+    expect(link.websiteUrl).toBe("https://my-note.example");
+  });
+
+  it("does not guess when presets sharing the address link to different pages", () => {
+    const link = render({
+      presetEntries: [
+        ...entries,
+        claudePreset(
+          "hub-plan",
+          "https://hub.example.com",
+          "https://hub.example/plan",
+        ),
+      ],
+      formBaseUrl: "https://hub.example.com",
+      formWebsiteUrl: "https://my-note.example",
+    });
+    expect(link.websiteUrl).toBe("https://my-note.example");
+  });
+
+  it("does not guess when presets sharing the link differ in promotion", () => {
+    const link = render({
+      presetEntries: [
+        ...entries,
+        claudePreset(
+          "hub-2",
+          "https://hub.example.com",
+          "https://hub.example/key?ref=cc",
+        ),
+      ],
+      formBaseUrl: "https://hub.example.com",
+      formWebsiteUrl: "https://my-note.example",
+    });
+    expect(link.websiteUrl).toBe("https://my-note.example");
+    expect(link.partnerPromotionKey).toBeUndefined();
+  });
+
+  it("a selected preset still wins over the base URL lookup", () => {
+    const link = render({
+      presetEntries: entries,
+      selectedPresetId: "other",
+      formBaseUrl: "https://hub.example.com",
+    });
+    expect(link.websiteUrl).toBe("https://other.example/key");
+  });
+
+  it("reads each app's preset address from its own field", () => {
+    const codex = render({
+      appId: "codex",
+      presetEntries: [
+        {
+          id: "codex-0",
+          preset: {
+            name: "Hub",
+            websiteUrl: "https://hub.example",
+            apiKeyUrl: "https://hub.example/codex-key",
+            category: "aggregator",
+            auth: {},
+            config:
+              'model_provider = "custom"\n\n[model_providers.custom]\nbase_url = "https://hub.example.com/v1"\n',
+          },
+        } as unknown as Entries[number],
+      ],
+      formBaseUrl: "https://hub.example.com/v1",
+    });
+    expect(codex.websiteUrl).toBe("https://hub.example/codex-key");
+
+    const desktop = render({
+      appId: "claude-desktop",
+      presetEntries: [
+        {
+          id: "claude-desktop-0",
+          preset: {
+            name: "Hub",
+            websiteUrl: "https://hub.example",
+            apiKeyUrl: "https://hub.example/desktop-key",
+            category: "aggregator",
+            baseUrl: "https://hub.example.com",
+          },
+        } as unknown as Entries[number],
+      ],
+      formBaseUrl: "https://hub.example.com",
+    });
+    expect(desktop.websiteUrl).toBe("https://hub.example/desktop-key");
+  });
+});